Need help to scroll when mouse wheel is used. Scroll Up or Down as per mouse action. I'm trying to create  moveUp() &   moveDown() function,  to scroll according mouse wheel action On scroll, remove class of current div :- .active and add class :- .active to scrolled div (div in viewport), by default first div has class .active. See the Pen zXZKYN by tun712 (@tun712) on CodePen